Today, a majority of the wastegate pressure or vacuum actuators are made by using a diaphragm. The drawbacks of these designs are that the shaft allows for only a few degrees of angular freedom and no rotation. Side loading and torsional forces will shorten the life and performance of a diaphragm actuator and limit their application. Diaphragms are like a spring, the more you compress or extend a spring, the more force it takes. Diaphragms are similar to springs because the further you travel with a diaphragm, the more force it takes to move it. Diaphragm actuators usually also include a return spring which compounds the effort required to move the actuator. There is always going to be a limit to travel with a diaphragm actuator because the stretch allowed by the rubber diaphragm is limited.
Accordingly, there is a need for improved actuators to operate wastegates with increased degrees of angular freedom and rotation of the shaft and that can accept side loading forces and torsional forces.